Cooling dental materials

ABSTRACT

There is disclosed apparatus for cooling dental materials preparatory to mixing a thermoelectric cooling device is disposed in cooling relation to a support for receptacles containing the dental material and in cooling relation to a removable platform on which the materials are mixed. Another mixing platform is provided out of cooling relation to the thermoelectric cooler.

[Ill 3,712,072

Jan. 23, 1973 United States Patent n 1 Hoge etal.

[56] References Cited 15 1 coouuc DENTAL MATERIALS UNITED STATES PATENTS ['75] inventors: Henri" H. liege, Baltimore, Md.

mm "U u "A mm m mm mm mu n n u e an MWDC 3 6% m w999 /HHH H2511 6 8 %8 1 4]] I355 ,22 333 a s s w w A A O O C C m A "M M mm .m u G w w [73] Assignee: Rhomega Systems, Inc.,

Primary ExaminerWilliam J. Wye Attorney-Colton & Stone "[551 WEHT Xpi-iIZBJMI App]. No.1 136,855

[57] ABSTRACT There is disclosed apparatus for cooling dental materials preparatory to mixing a thermoelectric cooling 32/39,

[52] US. Cl. 32/] device is disposed in cooling relation to a support for receptacles containing the dental material and in cool- .F25b 21/02 ing relation to a removable platform on which the 32/1 40 39 materials are mixed. Another mixing platform is pro- [58] Field of Search vided out of cooling relation to the thermoelectric cooler 6 Claims, 4 Drawing Figures PATENTEDJAN 23 I975 SHEET 1 BF 2 INVENTORS. HENRI H. HOGE GILBERT A. WADSWORTH ATTORNEYS.

PATENTEUJM 23 1915 SHEET 2 UF 2 ATTORNEYS.

BACKGROUND OF THE INVENTION This invention relates to cooling dental materials, particularly quick setting plastic filling materials such as Adaptics, and mixing the same. Adaptics are used by dentists as filling material.

The present technique for handling, storing and mixing adaptic material is to place the vials or containers of adaptic material in a dry ice carton and ship the same to the dentist. Upon receipt, the dentist removesthe adaptic vials from the dry ice carton and places the vials in a refrigerator. The purpose in keeping the material cold is to prolong its shelf life.

The practice of dentists in handling adaptic material diverges at this juncture. One technique now used is for the dental assistant to remove the adaptic vials from the refrigerator in the morning and place them in the treatment room. When it is desired to mix the adaptic materials in filling a tooth, the dentist removes a desired portion from the separate containers, places it on a suitable mixing platform and mixes the materials. This technique has two substantial disadvantages. The first disadvantage is that the temperature of the adaptic material gradually assumes the ambient temperature in the treatment room thereupon decreasing the ultimate shelf life of the material. The second disadvantage is that the reaction of the materials, during the mixing process, is acceleratedat higher temperatures. It is not uncommon for the adaptic material to set up and harden within two or three minutes after mixing if the adaptic material'is at room temperature before mixing. Consequently, the dentist must quickly place the mixed adaptic material in the tooth to be filled. Otherwise, the dentist ends up with a pile of hardened adaptic on the mixing platform and must start again.

The second technique now widely used is for the adaptic materials to remain in the refrigerator until the dentist is ready to prepare a filling. The vials are removed from the refrigerator and portions removed I dentist must allow the material to warm up slightly so that it becomes pliable and mixable.

Of interest is the disclosure of U.S. Pat. No. 3,230,723 which discloses a thermoelectric cooling apparatus for mixing dental cements. As disclosed therein, dental cements must be mixed at a precise temperature in order to develop optimum strength, resistance to erosion in oral fluids and other important properties. This reference provides a cooled metal slab where mixing of the dental cement takes place.

In contrast, this invention provides a location for cooling the vials of dental material to prolong shelf life, provides a cooled mixing platform for mixing the dental materials to providea prolonged reaction time and also provides an uncooled mixing: platform to provide a short reaction time for the dental materials.

SUMMARY OF THE INVENTION It is an object of this invention to provide an ap-' paratus for cooling dental materials preparatory to mixing thereof in order to prolong the shelf life of the materials and to regulate the reaction time thereof.

Another object of the invention is to provide an ap-' paratus for cooling dental materials including a removable mixing platform comprising a multiplicity of sheets and thermoelectric cooling means for cooling the mixing platform and receptacles containing the dental material.

In summary, the apparatus of this invention comprises a housing providing means for receiving a plurality of receptacles having therein the dental material; a removable mixing platform positioned in the housing and comprising a multiplicity of sheets; thermoelectric cooling means having a cold side, in heat conducting relationship with the receiving means and the platform for cooling the receiving means and the mixing platform below ambient, and a hot side; and means in heat exchanging relation with the hot side of the thermoelectric cooling means for dissipating the heat produced thereby.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded isometric view of the apparatus of this invention;

FIG. 2 is a top view of the device of FIG. 1, the lid thereof being broken away for clarity;

FIG. 3 is a cross sectional view of the device of FIG. 2 taken substantially along line 3-3 thereof as viewed in the direction indicated by the arrows; and

FIG. 4 is another cross sectional view of the device of FIG. 2 taken substantially along line 4-4thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus 10 of this invention comprises as major components a housing 12 for receiving a plurality of receptacles 14 having dental material therein, a removable mixing platform 16 in the housing, thermoelectric cooling means 18 for cooling the receptacles l4 and the mixing platform 16 and means 20 for dissipating the heat produced by the thermoelectric cooling means.

The housing'l2 conveniently includes a.lower section 22 having feet 24 thereon, an upper section 26 positioned with respect to the lower section 22 to provide a compartment 28 for accommodating certain components of the apparatus 10 as will be more fully apparent hereinafter and a lid 30. As shown best in FIGS. 3 and 4, the lid 30 is mounted for movement between a position closing the housing 12 and cooperating with the upper housing section 26 to provide a cooled compartment 32 and an open position allowing access to the interior of the housing 12 The housing components'are made in any suitable manner from any suitable material, such as by vacuum molding an organic resin.

cooled well 40 for receiving a second mixing platform 42 and an uncooled well 44 for receiving other mixing equipment such as a spatula (not shown) or the like. As shown best in FIGS. 3 and 4, the cooled compartment 32 is insulated on the under side thereof by suitable insulating material 46.

The lid 30 is mounted on the upper housing section 26 in any suitable fashion, as by pivoting the lid 30 about a rod 48 extending between a pair of cars 50 which project upwardly from the housing section 26. Affixed to the inside of the lid 30 is a closure 52 for the cooled compartment 32. As shown best in FIG. 3, the closure 52 includes a sealing lip 54 for engaging the housing section 26 between the cooled well 38 and the uncooled spatula well 44. As shown best in FIG. 4, the closure 52 includes a sealing lip 56 for engaging the housing section 26 between the receptacle location and the uncooled well 40. As may be seen in FIG. 2, the closure 52 engages the housing section 26 along an imaginary line 58 encompassing the cooled compartment 32. The closure 52 is conveniently made of heat insulating material so that the temperature in the cooled compartment 32 is conveniently controlled by the thermoelectric cooling means 18.

The first mixing platform 16 comprises a multiplicity of sheets of low thermal conductivity material such as paper or the like. As shown best in FIG. 3, the mixing platform 16 resides in the cooled compartment 32 and, for reasons more fully pointed hereinafter, assumes essentially the same temperature as the receptacles 14. Experimentation with a model of this invention reveals that the top sheet of paper from the mixing platform 16 retains essentially the temperature of the cooled compartment 32 for about 15 minutes after the platform 16 is removed from the cooled well 38 and placed at a location of ambient temperature. It thus appears that the dentist using the apparatus of this invention has a reasonable length of time in which to remove the platform 16, remove dental materials from the receptacles l4 and begin the mixing thereof before the pad 16 appreciably changes temperature.

As heretofore mentioned, mixing the cooled dental materials on the cool mixing pad 16 prolongs the reaction time of the materials thereby affording the dentist a reasonable length of time to perform the chore at hand. For example, with typical presently available adaptic material cooled to about 55 and the mixing platform 16 at essentially the same temperature, the dentist has about 10 minutes after mixing in which to insert the material in the patients tooth before the material sets up and loses pliability. When the dentist desires a shorter reaction time, he may mix the adaptic material on the uncooled mixing platform 42 and obtain a set up time of about 5 minutes. Accordingly, the provision of cooled and uncooled mixing platforms provides an additional capability.

To illustrate the difference between this invention and that disclosed in U.S. Pat. No. 3,230,723, it is first assumed that the dentist normally stores the adaptic material in a conventional refrigerator, removes it in the morning and places it in the treatment room for use throughout the day. The temperature of the adaptic material accordingly approaches ambient before mixing. If the dentist mixes the adaptic material in the housing disclosed in U.S. Pat. No. 3,230,723, he must wait a significant length of time for the temperature of the adaptic material to subside to a temperature of about 55. This obviously may consume l5 to 30 minutes unless the dentist has the foresight to place the material on the mixing slab substantially before he is ready to mix the materials. This procedure is faulty since the dentist will likely fail to precool the adaptic material and will thereby achieve a relatively short set up time of undetermined length.

If the dentist makes a practice of keeping the adaptic material in the refrigerator until just before use, the adaptic material will be at a temperature approximating that of the refrigerator which is typically about 38. If the dentist removes the adaptic material from the refrigerator, immediately places the adaptic material on the mixing slab of U.S. Pat. No. 3,230,723, he will find that the adaptic material is not pliable enough since its temperature will be somewhere between the temperature of the refrigerator and the setting of the temperature control of the mixing slab.

It will accordingly be appreciated that there are many uncertainties involved in mixing adaptic materials unless the adaptic materials and the mixing platform are cooled at all times at the desired mixing temperature. It will be appreciated that waiting for the adaptic material to cool off in the event the materials are normally kept at room temperature, or warm up if the materials are normally kept refrigerated, introduce so many uncertainties that the reaction time of the adaptic material cannot be predicted with any degree of certainty.

The thermoelectric cooling means 18 comprises a thermoelectric cooling module 60 of any suitable design. Commercially available thermoelectric modules include a cold side, a hot side and a semiconducting material disposed therebetween. The cooling of the cold side takes place due to the Peltier effect. As shown in FIGS. 1 and 2, the thermoelectric module 60 extends through an aperture 62 in the upper housing section 26 so that the cold side thereof is in heat exchanging relation with a thermally conductive cold plate 64 disposed in the cooled compartment 32. The hot side of the thermoelectric module 60 is in heat exchanging relation with a heat conductor 66 comprising part of means 20 for dissipating heat produced by the hot side of the thermoelectric module 60. The thermoelectric module 60, cold plate 64 and heat conductor 66 may conveniently be secured to the housing section 26 by one or more fasteners 68.

The cold plate 64 includes a planar section 70 extending under and supporting the receptacles 14. As shown in FIGS. 1 and 3, the cold plate 64 comprises a section 72 extending into the cold well 38 and including a lip 74 thereon for supporting the mixing platform 16. It will be apparent that the cold plate 64 is'in heat exchanging relation with the receptacles l4 and the mixing platform 16.

As will be apparent to those skilled in the art, a suitable power supply must be provided for the thermoelectric module 60. This power supply conveniently converts nominal 1 l5 volt 60 cycle single phase alternating current into direct current. Since many approaches are known in the prior art to accomplish this function, one example being in U.S. Pat. No. 3,230,723, disclosure of the power supply is deemed unnecessary. it will also be apparent that an alternating current powered thermoelectric module may be used as shown in U.S. Pat. No. 3,1 1 1,008. It is sufficient to say that the apparatus conveniently includes means for converting conventionally available alternating current into direct current to energize the thermoelectric module 60 including a v thermostat 76 extending through an aperture 78 in the upper housing section 26 into heat exchanging relation with the cold plate 64 for energizing and deenergizing the module 60 in accordance with a temperature selector (not shown). This power supply may conveniently reside in the compartment 28 provided by the lower housing section 22.

The heat dissipating means comprises the heat conductor 66, a fan 80 and an air path through the housing 12 to circulate ambient air across the heat conductor 66 and thereby dissipate the heat produced by the hot side of the thermoelectric module 60. The air path conveniently comprises an exit 82 in the upper housing section 26 (FIG. 3) to allow air flow out of the housing 12 as suggested by the arrow in FIG. 2. The air path comprises a pair of inlets 84, 86 located in the upper housing section 26 and the lid respectively as shown in FIG. 1. Air entering through the inlet 84 passes across the heat conductor 66, through the fan 80 and out the exit 82. Air passing through the inlet 86 flows through a plurality of apertures 88 in the bottom of the uncooled well 40, across the heat conductor 66, through the fan 80 and out the exit 82. The auxiliary air path afforded by the inlet 86 and the apertures 88 ensure that the uncooled pad 42 is at ambient tempera ture. Since dentists offices are now universally air conditioned, it may be reasonably assumed that the temperature of the uncooled pad 42 is in the range 70-7 6 F. This is substantially warmer than the cooled pad 16 and is sufficient to accelerate the set up time of presently used adaptics.

In practice, the power supply of the apparatus 10 is connected to a suitable power source to energize the thermoelectric module 60. The receptacles 14 are placed on the cold plate64 as shown in FIG. 2. The mixing platforms 16, 42 are placed in the cooled and uncooled wells 38, respectively as shown in FIGS. 3 and 4. After the lid 30 is closed and the apparatus 10 operates for a reasonable length of time, the receptacles l4 and the platform 16 cool off to a predetermined temperature. The uncooled platform 42 remains at ambient temperature.

When the dentist is ready to mix the adaptic material, he decides whether a long or short set up time is desirable. Based on this decision, either the cooled platform 16 or the uncooled platform 42 is removed from the housing 12 and placed on a convenient support. Adaptic material from the appropriate receptacle [4 is removed and placed on the mixing platform and mixed. After the desired amount of adaptic material has been used by the dentist, the soiled sheet of the mixing platform is torn off and the platform is returned to its appropriate well in the housing 12.

It will be seen that there is herein provided an improved method and apparatus to prepare dental materials for mixing. I

We claim:

1. An apparatus for cooling dental materials preparatory to mixing thereof comprising a housing providing means for receiving a pluralty of dental material containing receptacles; a removable mixing platform positioned in the housing and comprising a multiplicity of sheets;

thermoelectric cooling means having a cold side, in heat conducting relationship with the receiving means and the platform for cooling the receiving means and the mixing platform below ambient, and the hot side;

means for dissipating the heat produced at the hot side of the thermoelectric cooling means.

2. The apparatus of claim 1 wherein the housing comprises a first insulated compartment and a second compartment;

the first mixing platform and the receiving means reside in the insulated compartment;

the heat dissipating means resides in the second compartment; and further comprising a second removable mixing platform residing in the second compartment.

3. The apparatus of claim 2 wherein the heat dissipating means comprising a heat conductor in contact with the hot side and means providing an air path through the second compartment, the air path including an inlet section upstream of the heat conductor and an outlet section downstream of the heat conductor, the inlet section passing in heat exchanging relation to the second mixing platform.

4. The apparatus of claim 1 further comprising a second removable mixing platform residing in the housing; and

means for maintaining the second platform at ambient temperature.

5. The apparatus of claim 4 wherein the maintaining means comprises a compartment in the housing open to the atmosphere and means for circulating ambient air through the housing, the second mixing platform being located in the compartment.

6. The apparatus of claim 1 wherein the sheets are of low thermal conductivity material. 

1. An apparatus for cooling dental materials preparatory to mixing thereof comprising a housing providing means for receiving a pluralty of dental material containing receptacles; a removable mixing platform positioned in the housing and comprising a multiplicity of sheets; thermoelectric cooling means having a cold side, in heat conducting relationship with the receiving means and the platform for cooling the receiving means and the mixing platform below ambient, and the hot side; means for dissipating the heat produced at the hot side of the thermoelectric cooling means.
 2. The apparatus of claim 1 wherein the housing comprises a first insulated compartment and a second compartment; the first mixing platform and the receiving means reside in the insulated compartment; the heat dissipating means resides in the second compartment; and further comprising a second removable mixing platform residing in the second compartment.
 3. The apparatus of claim 2 wherein the heat dissipating means comprising a heat conductor in contact with the hot side and means providing an air path through the second compartment, the air path including an inlet section upstream of the heat conductor and an outlet section downstream of the heat conductor, the inlet section passing in heat exchanging relation to the second mixing platform.
 4. The apparatus of claim 1 further comprising a second removable mixing platform residing in the housing; and means for maintaining the second platform at ambient temperature.
 5. The apparatus of claim 4 wherein the maintaining means comprises a compartment in the housing open to the atmosphere and means for circulating ambient air through the housing, the second mixing platform being located in the compartment.
 6. The apparatus of claim 1 wherein the sheets are of low thermal conductivity material. 